Automobile brake



April 14, 1931. J. c. TUMLIN l AUTOMOBILE BRAKE Ff'iled Dec.

nve ntor .farm i Tum h'lz t Il Attorneys Patented Api'. 14, 1931 `UNHTSTATES JAMES C. TUIVILIN, F BIRMINGHAM, .ALABAMA AUTGll/IBJLE BRAKEApplication filed Becernber 8, 1928. Serial No. 324,680.

My invention relates to brakes, more particularly to brakes of therotary drum type suoli as are employed with automobiles, and has for itsobject the provision of apparatus of the character designated whichshall be simple of construction and which shall be effective to provideuniform frictional engagement of the brake shoes with the drumthroughout the length of the shoes.

A further object of my invention is to provide a brake of the rotarydrum, internal shoe type wherein the shoes are brought into uniformfrictional engagement with the drum and wherein simple effective meansfor adjusting the brake is provided.

A further object of my invention is to provide an automobile brake ofthe rotary drum,

internal shoe type wherein means are provided for actuating the sliceswhich shall `be effective to cause the shoes to exert a uniform pressurethroughout their lengths against the bralre drum.

A still further object of my invention is to provide an automobile brakeof the rotary drum, internal brake shoe type wherein the brake shoes aresupported on radial supports which are inclined outwardlyiin a planeparallel with the plane of rotation of the drum, together with means foractuating the shoes on the supports whereby they are forced outwardlyand uniformly to engage the brake drum.

e. still further object of my invention is to provide an automobilebrake which em a5 bodies a readily controllable selfgenerative force inapplyingit, thereby greatly reducing the force required to operate it.

Briefly, my invention comprises a rotary brake drum which is secured tothe automobile wheel and which is provided with inrection parallel tothe plane of `rotation of the drum, and the brake shoes being providedwith feet which are inclined in a direction parallel to their respectivesupports. In applying the brake, the shoes are actuated 5o in adirection to move them outwardly on their supports whereby they arebrought into uniform frictional engagement with the brake drum. Thebrakes are released by means of conventional springs.

Apparatus embodying features of my invention is illustrated in theaccompanying drawings, forming a part of this application, wherein Fig.1 is a vertical sectional view of a prake made in accordance with myinvenion;

Fig. 2 is a sectional view taken along the line II-II of Fig. 1; and

Fig. 3 is a view similar to Fig. 1 showing a modified form of myinvention.

Referring to the drawings for a better understaiiding of my invention, 1show a rotary bralre drum 10 adapted to be secured to a wheel, notshown, by means of bolts 11. The vehicle with which the brake isassociated is assumed to be going ahead when the drum 10 is rotating inthe direction shown by the arrow.

Located within the drum 10 are brake shoes 12 and 13 which are providedwith the usual lining 14. As shown in Fig. 1, the brake shoe 12 is mademuch longer than the bralre shoe 18 for a purpose which will shortlyappear.

At 16 is shown a conventional axle housing upon which is supported adisk 18 which is made a fairly close fit with the interior of the drumlOso as to prevent water or dirt from getting to the interior of the drum.Carried by the disk 18 are a plurality of radial brake shoe supports 19which cooperate with the brake shoe 12 and a lesser number of radialsupports 21 which cooperate with the brake shoe 13. rflic brake shoesupports 19 are provided with supporting surfaces 22 which are inclinedin a plane parallel with the plane of rotation of the drum and outwardlyin the direction of ahead rotation of the drum, while the brake shoesupports 21 are provided with supporting surfaces 23 which are inclinedoutwardly in a reverse direction to that of the surface 22.

The brake shoe 12 is provided with feet 211 cooperating with thesupports 19 and having surfaces 26 which engage with the surT faces 22of the supports 19, and which are iiifil) lUO

s direction to pull them inwardly of the drum 10 by means of a pluralityo-f springs 32 which are anchored to pins 33 secured to the disk 18. m

cess-ive vibration and rattling of the parts. Journaled inthe upper partof the disk 18 vis a rock shaft 36 carrying on its end inside Vthe drum10 a cam 37. Carried on the outer end of the shaft 36 is an arm38 havingprovided at its lower end a hole 39 to which may be secured actuatingmeans, not shown. The outer end of the shaft is provided withlongitudinal grooves shown at around which the upper end of the arm 38is adjustably clamped by `means of a bolt 40. lThe cam 37 bears againstthe inturnedupper ends 41 and 412 of the brake shoes 12 and 13respectively. yThe opposite ends of the brake shoes are normally biasedapart by means of a spring 43 -seated in recesses 14 and1erespectivelyin the brake shoes 12 and 13.

f In the operation of my improved brake,- the cam 37 is partiallyrotated by means of the arm 38 to spread the upper ends of the brakeshoes 12 and 13V apart. ,As the brale Yshoes s read a art the feet 24move outwardly on the inclined planes formed by the supporting surfaces22 of the supports 19 and the bralre shoe 12v is brought into uniformfrictional engagement with the drum 10. Likewise, the brake shoe 13 Aismoved outwardly along the inclined planes defined by the supportingsurfaces 23 of the supports 21. In `designing the brake the angles ofinclination and the distances of the same throughout their lengths fromthe center of the axle housing are made equal so that the brralre shoesmove out uniformly when being applied and engage the brake drum 10 withan equal force throughout. UponV turning the cam 37 in the oppositedirection, the springs 32 pull the brake shoes back down the inclinedplanes, or inwardly of the brake drum to release the brakes. Y

As has already been pointed out, the surfaces 22 diverge outwardly fromthe center of the housing when considered inV the general direction ofahead rotation ofthe drum 10, while the surfaces 28 of the supports 21incline inwardly when considered in the direction of ahead rotation andoutwardly in the direction of reverse rotation of the drum 10, orreverse to the direction of inclination ihe springs 32 also serve toprevent ex-i of the surfaces 22. The purpose of so directing theinclinations of the supporting arm is to provide a brake which isself-generative of force. When the brake is being applied, while thedrum 10 is rotating in the direction shown by the arrow, the brake shoe12 frictionally engages thev drum and the drum v10 then aids the cam 27in pulling the brake lshoe around with the drum and outwardly on thesupporting surfaces 22. Likewise, when the brake is being applied withthe drum 10 rotating in a reversedirection, the feet 27 move Indesigning the brake, the ang-le of inclination of the brake shoesupports determines the degree of force self-generated when applying thebrake. Itiwillaccordingly be apparent'that the self-generative force ofthe brake isreadily controllable by alteringthe angle of inclination.

To adjust the brake, the arm 38 is seton the shaft 36 in the desiredoperating position with the cam 37 forcing the brake shoes sufficientlyapart for them to be ust out of frictional engagement with the drum 10.

The apparatus vshown in Fig. 3 is simila to that shown' in F ig. 1,except that instead of providing one long brake shoe 12 and oneshortbrake shoe 13, I'provide three brake shoes 51, 52 and 53.- 'T-hethree brake shoes are supported in the same manner as already describedfor the brake shoes 12 and 13 of Figi 1. In this modification, however,the brake shoes 51 and 5 2 are pivotally connected together atV 56While'the connected brake shoes V51 and 52 are normally biased awayfromthe shoe 53 by aspring 58 which is similar to the spring 43. Theconstruction shown in this figure of the drawing maybe advantageouslyemployed with brake drums which are slightf ly out of round, thegreaterV number of shoes used and their pivotal connection providing Vagreater flexibility than is possible to obtain withthe one longbrake'shoe 12 shown in Fig. 1. Otherwise the' 'operation andconstruction of the two modifications are the same. I Y .Y

From the foregoing, itwill be apparent that I have devised an improvedautomobile brake whichis simple of construction and adjustment, easyvjofmanufacture, and by y f' means of which a uniform braking pressure maybe obtained around the entire periphery of the brake drum. y

While I have shown my inventionv in buiJ two forms, itwill be obvious tothose skilled in the art that it is not so limited but is susceptible ofvarious other changes and modilications, without departing from thespirit thereof, and I desire therefore that only such limitations shallbe placed thereupon as are imposed by the prior art, or as arespecifically set forth in the appended claims.

What I claim is:

l. In a brake of the character described, a brake drum, an axle housing,a plurality of radially extending brake shoe supports supported i'romthe axle housing and having ytheir outer ends inclined in a planeparallel to the plane of rotation of the drum, some of said supportsbeing inclined outwardly in the direction of the ahead rotation of thedrum and the others inclined in a reverse direction, brake shoes carriedby the supports in a position to cooperate with the drum, the area ofthe brake shoe cooperating with the supports inclined in the directionof ahead rotation comprising the major brake shoe areas, and means foractuating the brake shoes on the supports to bring them into 'rictionalengagement with the brake drum.

2. In a brake of the character described, a brake drum, an axle housing,a plurality oi radially extending brake shoe supports supported from theaxle housing and having their outer ends inclined in a plane parallel tothe plane of rotation of the drum, the greater number of said supportsbeing inclined outwardly in the direction of the ahead rotation of thedrum and the lesser number inclined in a reverse direction, a pair oi'brake shoes of difterent lengths carried by the supports in a positionto cooperate with the drum, the shoe of greater length cooperating withthe supports inclined in the direction or ahead rotation, and means foractuating the brake shoes on the supports to bring them into rictionalengagement with the brake drum.

3. In a brake of the character described, a brake drum, an axle housing,a plurality of radially extending brake shoe supports supported from theaXle housing and having their outer ends inclined in a plane parallel tothe plane of rotation of the drum, the greater number et said supportsbeing inclined outwardly in the direction of the ahead rotation oit' thedrum and the lesser number inclined in a reverse direction, brake shoescarried by the supports in a position to cooperate with the drum, thegreater brake shoe area cooperating with the supports inclined in thedirection oi ahead rotation, means for actuating the brake shoes on thesupports to bring them into frictional engagement with the brake drum,and resilient means to actuate the brake shoes in the opposite directionto bring them out of frictional engagement.

i. In a brake oi the character described, a brake drum, an axle housing,a plurality o'l' radially extending brake shoe supports supported fromthe axle housing and having their outer ends inclined in a planeparallel to the plane of rotation of the drum, the greater number ofsaid supports being inclined outwardly in the direction oi the aheadrotation of the drum and the lesser number inclined in a reversedirection, brake shoes rlocated within the drum in a position tofrictionally engage therewith, the greater brak-e shoe area cooperatingwith the supports inclined in the direction of ahead rotation, feetcarried by the brake shoes and resting on the supports, said feet beinginclined in a direction parallel to their cooperating supports, andmeans to actuate the brake shoes on the supports to bring them intofrictional engagement with the brake drum.

5. In a brake of the character described, a brake drum, an axle housing,a plurality of radially extending brake shoe supports supported from theaxle housing and having their outer ends inclined in a plane parallel tothe plane oi rotation of the drum, the greater number of said supportsbein@ inclined outwardly in the direction of the ahead rotation of thedrum and the lesser number inclined in a reverse direction, brake shoeslocated within the drum in a position to frictionally engage therewith,a greater length of brake shoe cooperating with the supports inclined inthe direction of ahead rotation, feet carried by the brake shoes andresting on the supports, said feet being inclined in a directionparallel to their cooperating supports, means to actuate the brake shoeson the supports to bring them into frictional engagement with the brakedrum, and springs to actuate the brake shoes in the opposite direction.

In testimony whereof I aHX my signature..

JAMES C. TUMLIN.

